1. Field of the Invention
The present invention relates to a method of surface protection of a semiconductor substrate for maintaining a clean surface of a semiconductor substrate, in particular silicon semiconductor substrate in a condition in which it is not contaminated with organic substances.
1. Description of Related Art
Typically, in a prior art method of cleaning a semiconductor substrate, a highly clean surface condition is produced by removing the natural oxide film and contaminating substances using chemicals such as hydrofluoric acid, ammonia/hydrogen peroxide, sulfuric acid/hydrogen peroxide, or hydrochloric acid/hydrogen peroxide. In recent years, with advances in semiconductor integration, it has become necessary to perform higher semiconductor surface cleanness and maintain such a condition.
Specifically, various types of contaminating substances adhere to the surface of a semiconductor substrate during the manufacturing steps, so, in order to respond higher integration, it has become necessary not only to remove minute particles of small diameter, metals or organic substances adhering in the manufacturing steps, but also to prevent adhesion of organic substances while the substrate is left to stand between washing and the next step.
Typically, organic substances are present in the air in the clean room and adhere readily and in a short time simply on exposure thereto. As a temporary method of preventing this, currently, a mini-environment technique or a method of organic substance removal using a chemical filter is employed.
However, the prior art methods described above are subject to the following problems. In the case of a mini-environment, a pot or the like is employed and the substrate must be held therein in a sealed condition, so the need for this pot and interfaces and so on for opening and closing the pot require enormous investment.
Also, chemical filters must be provided for example at the air inlet of the manufacturing device/clean room, and regularly changed, which also requires enormous investment.
In view of the above, an object of the present invention is to provide a semiconductor substrate surface protection method whereby the adhesion of contaminating substances in the stages after a clean surface has been obtained can be conveniently prevented and such a surface can be maintained without requiring enormous investment.